London, England (CNN) -- A South African has become so fat on her diet of marshmallows that she's been taken to England to lose weight.
She's "quite a character," her new caretakers say, but settling her into her new home has proven tricky -- she's an orangutan who has never seen another of her species before.
Oshine, the animal, arrived at the Monkey World Ape Rescue Center in southern England last week, the center announced on Twitter.
"We have a new arrival, very large & orange!" the center said September 1 -- but kept details close to its chest.
A day later, it said she was settling in well.
"Our new orange lady has spent the day in the nursery playroom today, she's doing really well but we have a long way to go, she is obese!
That's what a diet of marshmallows does, the center tweeted.
Weighing in at 100 kilograms (220 pounds), Oshine is "the largest orangutan in Britain today," the center said. She weighs about twice as much as she should, it added.
She'd been kept as a pet in South Africa for 13 years, the center explained. Her owner first contacted Monkey World for help in 2008.
The center has been working to bring Oshine to England since then, it said.
"The care that she received in South Africa was effectively misguided love," Monkey World Director Alison Cronin told CNN on Wednesday from the center in Wareham, England.
She explained that Oshine's previous owners had kept her as a pet, which she said is never a good idea with primates because they can become aggressive as they enter adulthood.
"Oshine's care became a problem because she was effectively left on her own for long periods of time during the day when the family weren't there to entertain her, and so they simply tried to keep her busy and happy by feeding her a lot of junk food -- so a lot of candy, a lot of sweets, and processed food," Cronin said.
"Because she was basically inactive and not flying around through trees and things, she put on an awful lot of weight, and now we have our work cut out for us here at Monkey World to get that weight off of her and to get her fit so that she, too, can become a breeding female and have a family of her own one day."
Late last month, "The Monkey World team went to Johannesburg, with a specially designed transport box, several days prior to the move" so the orangutan could get used to being in the box.
After two days of "playing" in the box, the door was shut for good and Oshine was on her way to a more natural life in England, the center said.
Only on Wednesday did the center finally post pictures of Oshine, revealing her to have such an enormous belly it looks difficult for her to move. A second photo showed her in a cage being moved by forklift to her new home.
The center is already itching to see progress, it admitted.
"It's very early days," its most recent tweet on Oshine says. "I so wish I had a magic wand!"
Cronin said the orangutan would be put on a special diet and, with luck, would find a mate at the center.
"Now that she is at the park, we have her on a healthy diet of vegetables and fruits and she is getting a lot more exercise climbing through" a section of the park designed for baby orangutans.
"It will take a few months for Oshine to reach a more appropriate weight and then she will be ready to meet a new man and consider a family of her own," she said.
Orangutans have the slowest metabolism of any of the great apes, even humans, Cronin said, making it a challenge for Oshine to lose the weight -- but as long as she is "getting all of the exercise and moving around as she should, the weight should start falling off naturally."